1. Technical Field
Embodiments consistent with the presently-claimed invention are related generally to navigation systems and surface measurement systems and, in particular, to methods and systems for performing navigation and terrain change detection based on real-time projection of a structured light pattern.
2. Discussion of Related Art
Automated vehicle navigation systems have become increasingly popular due, in part, to satellite navigation technologies like Global Positioning Systems (GPS). In some applications, satellite navigation systems, like GPS, may be combined or used in conjunction with surface measurement systems to detect environmental changes associated with a current travel route. Traditional surface measurement systems and methods may depend on the comparison of visual data (pictures) to identify changes in a visual landscape in order to identify potential obstacles. When an obstacle is identified, a vehicle operator may take steps to change the current travel route, deploy countermeasures, or take other actions to neutralize the potential impact of the obstacle. The accuracy of visual data, however, is easily compromised by such things as shadows, time of day, weather, and camera/lens inconsistencies. Therefore, comparisons of visual data is highly prone to misinterpretation (false positives and missed positives) that may be caused by inconsistencies in the visual data, rather than a change in the visual landscape.
Further, in some environments, the satellite navigation system used in conjunction with the surface measurement system may also suffer from misinterpretation or disruptions. For example, navigating a vehicle through a congested urban environment using GPS may be impractical due to restricted lines of sight to satellites. In other cases, unintentional disruptions in GPS service or a denial of GPS service may be caused by interference from electronic equipment, such as television broadcast transmitters or mobile phones. In some cases, however, denial of GPS service may be caused intentionally using jamming devices designed to interfere with the reliable reception of GPS transmission signals received by a GPS receiver. In some cases, visual data generated by a surface measurement system may be used to aid navigation during a disruption or a denial of GPS service. Yet, as previously mentioned, visual data generated by a surface measurement system may be corrupted by shadows, time of day, weather, or camera/lens inconsistencies. Consequently, visual data is often less accurate than the location information provided by a GPS service.
Thus, vehicle navigation systems, such as GPS, used in conjunction with surface measurement systems may have limited effectiveness in providing reliable navigation and an inconsistent ability to identify environmental changes to the landscape surrounding the traveling vehicle in some instances.